1 Monitoring Internet connectivity of Research and Educational Institutions Les Cottrell – SLAC/Stanford University Prepared for the workshop on “Developing Country Access to On-line Scientific Publishing", 4-5 October 2002, Trieste, Italy http://www.slac.stanford.edu/grp/scs/net/talk/ict p-02.html Partially funded by DOE/MICS Field Work Proposal on Internet End-to-end Performance Monitoring (IEPM), also supported by IUPAP
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Monitoring Internet connectivity of Research
and Educational Institutions
Les Cottrell – SLAC/Stanford UniversityPrepared for the workshop on “Developing Country Access to On-line
Scientific Publishing", 4-5 October 2002, Trieste, Italy http://www.slac.stanford.edu/grp/scs/net/talk/ictp-02.html
Partially funded by DOE/MICS Field Work Proposal on Internet End-to-end Performance Monitoring (IEPM), also supported by IUPAP
Outline• Measurement project initially created for HEP to
measure performance for various collaborations, extended to other physics & science collaborations– Value for planning, trouble shooting, setting expectations,
comparisons, setting SLAs etc.
• Methodology• Results
– Round trip times
– Loss
• Summary
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Measurement Architecture• Uses existing ubiquitous Internet ping infrastructure, no tools to install• Hierarchical vs. full mesh, each monitoring site chooses remote sites• Lightweight –
– low network impact (100bits/s/path)– no special machines– trivial to add monitored sites
– sends 21 pings each 30 mins to each chosen remote host
– Records RTT, loss, jitter, unreachable, out of order …
– Records data in local cache
• Archive host gathers data from measurements hosts regularly (at least daily)– Archives, analyzes and generates reports from data
– Make reports and data publicly available via the web
• Requirements:– Remote host: need a host accessible to pings, and a contact in case host does
not respond (almost no effort)
– Monitoring host: a low end host to make measurements, file space for cache, admin to install toolkit, choose remote hosts, build configuration file, respond to archivers in case unable to get data & keep it running (<<10% FTE)
– Archive site: probably about 20% of an FTE
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PingER deployment• Measurements from
– 34 monitors in 14 countries– Over 600 remote hosts– Over 72 countries – Over 3300 monitor-remote site pairs– Measurements go back to Jan-95– Reports on RTT, loss, reachability, jitter, reorders, duplicates …
• Countries monitored– Contain 78% of world population– 99% of online users of Internet– Mainly A&R sites
Monitoring Sites
Remote Sites
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User interface 1/2
Choose: metric, monitoring site(s), remote sites(s), time granularityShows colored values by time, allows downloading of results for further analysis
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User interface 2/2: PingER Group History Table
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PingWorld
Java applet at http://jas.freehep.org/demos/PingWorld/
(1) Macroscopic Behavior of the TCP Congestion Avoidance Algorithm, Matthis, Semke, Mahdavi, Ott, Computer Communication Review 27(3), July 1997
80% annual improvement ~ factor 10/4yr
~Factor 100 improvement in 8 years
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Detailed example of improvementsIncrease of bandwidth by factor of 460 in 6 years, more than kept pace - factor of 50 times improvement in loss
Note valleys when students on vacation
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Summary - results• Internet A&R connectivity performance is improving
– RTT 10-20%/yr, loss 50%/yr, throughput 80%/yr– Reduced use of satellites, mainly use for new hard to get to areas
(e.g. S. Russian Republics)
• China, S.E. Europe, Russia rate of change keeps up but several years behind
• India, S. America performance is where N. America & W. Europe were 4 – 5 years ago
• Africa limited continuous results (UCT & Wits. no longer respond): Uganda losses in last 2 years reduced from10% to 3%, RTT fairly constant at 800ms.
• Improvements need constant investments to understand & improve
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Summary - PingER• Lightweight (100bps/host pair, 21 pings/30mins per pair)• Very useful for inter-regional and poor links• Easy to deploy (uses ubiquitous Internet ping
infrastructure), however pings can be blocked• Easy to deploy for monitoring of sites in developing
countries– Remote sites ~ no effort (provide contact & host)
– Monitoring site small effort:1 day to download software set up & configure, (shared host) choose remote hosts to monitor, make data available for upload, check working, ongoing respond to emails.
– SLAC would be willing to assist
– Data public so anyone can do analysis/presentation of data
– Provide me (business card or email [email protected]) with contact and name of host to be monitored
Help• Looking for better hosts to monitor & contacts in:
– Albania, Armenia, Austria, Azerbaijan
– Macedonia*, Turkey*, Yugoslavia
– Columbia*, Venezuela*, Cuba, Mexico*
– Pakistan*
– Africa (apart from Egypt, Uganda & South Africa, n.b. according to http://www3.sn.apc.org/africa/afrmain.htm all 54 countries in Africa now have Internet access in capitals)
– Note there are a few countries (about 5% of the world’s countries) that do not have full Internet connections and pay dearly by the byte.
• A couple of years ago these included: Afghanistan, Western Sahara, Christmas Island, S. Georgia, Marshall Islands, Myanmar, Montserrat, N. Korea, Pitcairn, St Vincente & Grenadines